title: A hybrid approach to determining cornea mechanical properties in vivo using a combination of nano-indentation and inverse finite element analysis.
abstract: An analysis of the material properties of porcine corneas has been performed. A simple stress relaxation test was performed to determine the viscoelastic properties and a rheological model was built based on the Generalized Maxwell (GM) approach. A validation experiment using nano-indentation showed that an isotropic GM model was insufficient for describing the corneal material behaviour when exposed to a complex stress state. A new technique was proposed for determining the properties, using a combination of nano-indentation experiment, an isotropic and orthotropic GM model and inverse finite element method. The good agreement using this method suggests that this is a promising technique for measuring material properties in vivo and further work should focus on the reliability of the approach in practice.
authors.affiliation: Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, UK. Electronic address: m.haghihi-abayneh@lboro.ac.uk.
authors.forename: M H
authors.initials: MH
authors.lastname: Abyaneh
authors.forename: R D
authors.initials: RD
authors.lastname: Wildman
authors.forename: I A
authors.initials: IA
authors.lastname: Ashcroft
authors.forename: P D
authors.initials: PD
authors.lastname: Ruiz
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003315:Cornea; D004548:Elasticity; D020342:Finite Element Analysis; D008422:Materials Testing / Q000295:instrumentation*; D055595:Mechanical Phenomena; D036103:Nanotechnology / Q000295:instrumentation*; D013314:Stress, Mechanical; D013552:Swine; D014783:Viscosity
keywords: GM; Generalized Maxwell; Inverse Finite Element Method; Inverse finite element method; Inverse-FEM; NI; NT; Nano indentation; Nano-Indentation; Nasal-Temporal; Porcine cornea; Relax; Relaxation; SIA; Stress relaxation; Surgically Induced Astigmatism; UCVA; Uncorrected Visual Acuity